The process by which organisms with traits well suited to an environment survive and to produce offspring is

What is a sex-linked genetic disorder that disrupts the blood's ability to clot? a. achondroplasia b. huntington's disease c. hemophilia d. albinism

Rarefaction is used for which of the following? a. creating a representative sample b. studying how disease impacts populations c. rediscovering species thought to be instinct d. determining which sea creatures live in an area

Ihave no idea how to solve these. plus there's another question that is 2) a 10 kilogram meteorite is collected in space and brought back to earth. it is composed of 1.25 kg of uranium-238 and 8.75 kg of lead-206. how many u-238 half lives have passed? what is the approximate age of the meteorite?